1. Field of the Invention
The present invention relates to waterproofing membranes for installing tile, stone and other masonry products over surfaces including concrete, masonry, brick and plywood, and, in particular, to a high performance, strong, flexible, trowel applied waterproofing membrane for fast turnaround projects which can be flood tested in 24 hours and which does not require fabric reinforcement.
2. Description of Related Art
Water is known as one of the most destructive elements when it is not properly controlled and all structures which may come into contact with water must typically be protected from water seepage. A waterproofing membrane is used to prevent water seepage to the underlying structure and typical structures requiring waterproofing are bridge surfaces, roads, roofs, and the like. Other structures which must be protected against water seepage are swimming pools, fountains, shower pans and stalls, tubs, bathrooms, laundries, kitchens and food processing areas. Some applications require protection for both interior and exterior use.
For convenience, the following description will be directed to ceramic tile installations where the ceramic tile comes into contact with water and a waterproofing membrane is used to protect the underlying structure. For this type application, a waterproofing membrane is used over concrete, masonry, terrazzo, cement backer boards, gypsum boards (interior wall use only) and exterior grade plywood. Conventionally, the underlying substrate is overlaid with a fluid applied waterproofing membrane, covered with a reinforcing fabric and then overlaid with another layer of the fluid waterproofing membrane. Other methods employ a waterproofing membrane sheet. A mortar, typically a thin set mortar, is then applied over the waterproofing membrane surface and provides the base for installing ceramic tile. A grout is then used between the openings in the ceramic tile.
While the waterproofing membrane must of course provide a suitable waterproofing barrier, the waterproofing membrane must have other properties in order to be effective. For example, the waterproofing membrane should be strong, flexible to cover cracks in the substrate and not crack itself, be easy to apply and allow for rapid installation for fast turnaround projects. One of the most important properties is that the applied waterproofing membrane can be flood tested after 24 hours at 70° F. For this test the installer applies the waterproofing membrane and after 24 hours, a head of water (typically 10–12 inches) is placed on the membrane and the head is checked to determine if the waterproofing membrane is impermeable. Another important property is to pass ASTM D4068 which is a negative hydrostatic test under 2 feet of water. It is also preferred that the waterproofing membrane not require fabric at coves, drains or base or anywhere and can bridge gaps at least up to ⅛ inch. It is also important that the waterproofing membrane adhere to pipes and drains such as cast iron and lead. The waterproofing membrane should also have a tensile strength of at least 800–1200 psi and have an elongation of at least 30–50%.
The term “tile” will be used herein to refer to masonry products in general such as stone, bricks, pavers, and the like and the term “mortar” will be used herein to refer to thin-set mortars, medium bed mortars, underlayment or leveling mortars and grouts and pointing mortars.
It is known to incorporate fillers in waterproofing membranes as shown in U.S. Pat. No. 6,528,563 but Applicant is unaware of a waterproofing membrane which may be trowel applied and flood tested after 24 hours.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention is to provide an improved waterproofing membrane composition having enhanced overall application and performance properties, can be trowel applied at variable thicknesses, can be flood tested after 24 hours of application, pass ASTM D4068, not require any fabric, bridge gaps of up to ⅛ inch and adheres to materials such as cast iron and lead, metals without aid of another adhesive.
It is another object of the present invention to provide a method for making an improved waterproofing membrane composition and a method for using the waterproofing membrane composition of the invention.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.